Are solar panels worth it? Cost, output and payback

A typical home solar system is 3–4 kWp (kilowatt-peak). Installed prices vary widely by country, from roughly 1,000 to 3,000 per kWp in local currency; in Italy it is around €1,500–2,000 per kWp without a battery.

How much it produces

Output depends on sunshine. As a guide, each kWp produces per year about 900 kWh in London, 1,200 kWh in Milan, 1,400 kWh in southern Italy or Spain and 1,700+ kWh in sunny places like Phoenix or southern Australia. The calculator estimates it for your exact city from NASA solar data.

What it really saves

The key is self-consumption: every kWh you use while the sun shines is worth your full electricity price, while every kWh exported to the grid is usually worth much less. Without a battery, households typically self-consume 30–40% of their output.

Example in Milan: a 3 kWp system produces 3,600 kWh; with 35% self-consumption at €0.27/kWh and exports at €0.10/kWh it saves about €570 a year, paying back in 8–9 years before any incentives. Panels last 25–30 years, so the total return is solid.

How to use more of your own power

• Run the washing machine, dishwasher and water heater during sunny hours (timers or smart plugs help).
• Pair solar with a heat pump: it uses electricity when the sun is up.
• Consider a battery only if you use a lot of power in the evening: it raises self-consumption but lengthens payback.